1d7c4b398SAndrii Nakryiko /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2d7c4b398SAndrii Nakryiko 3d7c4b398SAndrii Nakryiko /* 4d7c4b398SAndrii Nakryiko * Internal libbpf helpers. 5d7c4b398SAndrii Nakryiko * 6d7c4b398SAndrii Nakryiko * Copyright (c) 2019 Facebook 7d7c4b398SAndrii Nakryiko */ 8d7c4b398SAndrii Nakryiko 9d7c4b398SAndrii Nakryiko #ifndef __LIBBPF_LIBBPF_INTERNAL_H 10d7c4b398SAndrii Nakryiko #define __LIBBPF_LIBBPF_INTERNAL_H 11d7c4b398SAndrii Nakryiko 12029258d7SAndrii Nakryiko #include <stdlib.h> 1385367030SAndrii Nakryiko 1485367030SAndrii Nakryiko /* make sure libbpf doesn't use kernel-only integer typedefs */ 1585367030SAndrii Nakryiko #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 1685367030SAndrii Nakryiko 1785367030SAndrii Nakryiko /* prevent accidental re-addition of reallocarray() */ 1885367030SAndrii Nakryiko #pragma GCC poison reallocarray 1985367030SAndrii Nakryiko 201d7a08b3SAndrii Nakryiko #include "libbpf.h" 211d7a08b3SAndrii Nakryiko 22d7c4b398SAndrii Nakryiko #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 23d7c4b398SAndrii Nakryiko ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 24d7c4b398SAndrii Nakryiko #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 25d7c4b398SAndrii Nakryiko #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 26d7c4b398SAndrii Nakryiko ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 27d7c4b398SAndrii Nakryiko #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 28d7c4b398SAndrii Nakryiko BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 29d7c4b398SAndrii Nakryiko BTF_INT_ENC(encoding, bits_offset, bits) 30d7c4b398SAndrii Nakryiko #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 31d7c4b398SAndrii Nakryiko #define BTF_PARAM_ENC(name, type) (name), (type) 32d7c4b398SAndrii Nakryiko #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 33d7c4b398SAndrii Nakryiko 34029258d7SAndrii Nakryiko #ifndef likely 35029258d7SAndrii Nakryiko #define likely(x) __builtin_expect(!!(x), 1) 36029258d7SAndrii Nakryiko #endif 37029258d7SAndrii Nakryiko #ifndef unlikely 38029258d7SAndrii Nakryiko #define unlikely(x) __builtin_expect(!!(x), 0) 39029258d7SAndrii Nakryiko #endif 40d7fe74f9SAndrii Nakryiko #ifndef min 41d7fe74f9SAndrii Nakryiko # define min(x, y) ((x) < (y) ? (x) : (y)) 42d7fe74f9SAndrii Nakryiko #endif 43d7fe74f9SAndrii Nakryiko #ifndef max 44d7fe74f9SAndrii Nakryiko # define max(x, y) ((x) < (y) ? (y) : (x)) 45d7fe74f9SAndrii Nakryiko #endif 464cedc0daSAndrii Nakryiko #ifndef offsetofend 474cedc0daSAndrii Nakryiko # define offsetofend(TYPE, FIELD) \ 484cedc0daSAndrii Nakryiko (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 494cedc0daSAndrii Nakryiko #endif 50d7fe74f9SAndrii Nakryiko 511bd63524SYonghong Song /* Symbol versioning is different between static and shared library. 521bd63524SYonghong Song * Properly versioned symbols are needed for shared library, but 531bd63524SYonghong Song * only the symbol of the new version is needed for static library. 541bd63524SYonghong Song */ 551bd63524SYonghong Song #ifdef SHARED 561bd63524SYonghong Song # define COMPAT_VERSION(internal_name, api_name, version) \ 571bd63524SYonghong Song asm(".symver " #internal_name "," #api_name "@" #version); 581bd63524SYonghong Song # define DEFAULT_VERSION(internal_name, api_name, version) \ 591bd63524SYonghong Song asm(".symver " #internal_name "," #api_name "@@" #version); 601bd63524SYonghong Song #else 611bd63524SYonghong Song # define COMPAT_VERSION(internal_name, api_name, version) 621bd63524SYonghong Song # define DEFAULT_VERSION(internal_name, api_name, version) \ 631bd63524SYonghong Song extern typeof(internal_name) api_name \ 641bd63524SYonghong Song __attribute__((alias(#internal_name))); 651bd63524SYonghong Song #endif 661bd63524SYonghong Song 67d72386feSAndrii Nakryiko extern void libbpf_print(enum libbpf_print_level level, 68d72386feSAndrii Nakryiko const char *format, ...) 69d72386feSAndrii Nakryiko __attribute__((format(printf, 2, 3))); 70d72386feSAndrii Nakryiko 71d72386feSAndrii Nakryiko #define __pr(level, fmt, ...) \ 72d72386feSAndrii Nakryiko do { \ 73d72386feSAndrii Nakryiko libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 74d72386feSAndrii Nakryiko } while (0) 75d72386feSAndrii Nakryiko 76be18010eSKefeng Wang #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 77d72386feSAndrii Nakryiko #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 78d72386feSAndrii Nakryiko #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 79d72386feSAndrii Nakryiko 80029258d7SAndrii Nakryiko /* 81029258d7SAndrii Nakryiko * Re-implement glibc's reallocarray() for libbpf internal-only use. 82029258d7SAndrii Nakryiko * reallocarray(), unfortunately, is not available in all versions of glibc, 83029258d7SAndrii Nakryiko * so requires extra feature detection and using reallocarray() stub from 84029258d7SAndrii Nakryiko * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates 85029258d7SAndrii Nakryiko * build of libbpf unnecessarily and is just a maintenance burden. Instead, 86029258d7SAndrii Nakryiko * it's trivial to implement libbpf-specific internal version and use it 87029258d7SAndrii Nakryiko * throughout libbpf. 88029258d7SAndrii Nakryiko */ 89029258d7SAndrii Nakryiko static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) 90029258d7SAndrii Nakryiko { 91029258d7SAndrii Nakryiko size_t total; 92029258d7SAndrii Nakryiko 93029258d7SAndrii Nakryiko if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) 94029258d7SAndrii Nakryiko return NULL; 95029258d7SAndrii Nakryiko return realloc(ptr, total); 96029258d7SAndrii Nakryiko } 97029258d7SAndrii Nakryiko 982ce8450eSAndrii Nakryiko static inline bool libbpf_validate_opts(const char *opts, 992ce8450eSAndrii Nakryiko size_t opts_sz, size_t user_sz, 1002ce8450eSAndrii Nakryiko const char *type_name) 1012ce8450eSAndrii Nakryiko { 1022ce8450eSAndrii Nakryiko if (user_sz < sizeof(size_t)) { 103be18010eSKefeng Wang pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 1042ce8450eSAndrii Nakryiko return false; 1052ce8450eSAndrii Nakryiko } 1062ce8450eSAndrii Nakryiko if (user_sz > opts_sz) { 1072ce8450eSAndrii Nakryiko size_t i; 1082ce8450eSAndrii Nakryiko 1092ce8450eSAndrii Nakryiko for (i = opts_sz; i < user_sz; i++) { 1102ce8450eSAndrii Nakryiko if (opts[i]) { 11112dd14b2SToke Høiland-Jørgensen pr_warn("%s has non-zero extra bytes\n", 1122ce8450eSAndrii Nakryiko type_name); 1132ce8450eSAndrii Nakryiko return false; 1142ce8450eSAndrii Nakryiko } 1152ce8450eSAndrii Nakryiko } 1162ce8450eSAndrii Nakryiko } 1172ce8450eSAndrii Nakryiko return true; 1182ce8450eSAndrii Nakryiko } 1192ce8450eSAndrii Nakryiko 1202ce8450eSAndrii Nakryiko #define OPTS_VALID(opts, type) \ 1212ce8450eSAndrii Nakryiko (!(opts) || libbpf_validate_opts((const char *)opts, \ 1222ce8450eSAndrii Nakryiko offsetofend(struct type, \ 1232ce8450eSAndrii Nakryiko type##__last_field), \ 1242ce8450eSAndrii Nakryiko (opts)->sz, #type)) 1252ce8450eSAndrii Nakryiko #define OPTS_HAS(opts, field) \ 1262ce8450eSAndrii Nakryiko ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 1272ce8450eSAndrii Nakryiko #define OPTS_GET(opts, field, fallback_value) \ 1282ce8450eSAndrii Nakryiko (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 1292ce8450eSAndrii Nakryiko 1306803ee25SAndrii Nakryiko int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 1316803ee25SAndrii Nakryiko int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 132cfd49210SMichal Rostecki int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 133d7c4b398SAndrii Nakryiko const char *str_sec, size_t str_len); 134d7c4b398SAndrii Nakryiko 135612d05beSAndrii Nakryiko int bpf_object__section_size(const struct bpf_object *obj, const char *name, 136612d05beSAndrii Nakryiko __u32 *size); 137612d05beSAndrii Nakryiko int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, 138612d05beSAndrii Nakryiko __u32 *off); 139612d05beSAndrii Nakryiko 1404cedc0daSAndrii Nakryiko struct btf_ext_info { 1414cedc0daSAndrii Nakryiko /* 1424cedc0daSAndrii Nakryiko * info points to the individual info section (e.g. func_info and 1434cedc0daSAndrii Nakryiko * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 1444cedc0daSAndrii Nakryiko */ 1454cedc0daSAndrii Nakryiko void *info; 1464cedc0daSAndrii Nakryiko __u32 rec_size; 1474cedc0daSAndrii Nakryiko __u32 len; 1484cedc0daSAndrii Nakryiko }; 1494cedc0daSAndrii Nakryiko 1504cedc0daSAndrii Nakryiko #define for_each_btf_ext_sec(seg, sec) \ 1514cedc0daSAndrii Nakryiko for (sec = (seg)->info; \ 1524cedc0daSAndrii Nakryiko (void *)sec < (seg)->info + (seg)->len; \ 1534cedc0daSAndrii Nakryiko sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 1544cedc0daSAndrii Nakryiko (seg)->rec_size * sec->num_info) 1554cedc0daSAndrii Nakryiko 1564cedc0daSAndrii Nakryiko #define for_each_btf_ext_rec(seg, sec, i, rec) \ 1574cedc0daSAndrii Nakryiko for (i = 0, rec = (void *)&(sec)->data; \ 1584cedc0daSAndrii Nakryiko i < (sec)->num_info; \ 1594cedc0daSAndrii Nakryiko i++, rec = (void *)rec + (seg)->rec_size) 1604cedc0daSAndrii Nakryiko 16128b93c64SAndrii Nakryiko /* 16228b93c64SAndrii Nakryiko * The .BTF.ext ELF section layout defined as 16328b93c64SAndrii Nakryiko * struct btf_ext_header 16428b93c64SAndrii Nakryiko * func_info subsection 16528b93c64SAndrii Nakryiko * 16628b93c64SAndrii Nakryiko * The func_info subsection layout: 16728b93c64SAndrii Nakryiko * record size for struct bpf_func_info in the func_info subsection 16828b93c64SAndrii Nakryiko * struct btf_sec_func_info for section #1 16928b93c64SAndrii Nakryiko * a list of bpf_func_info records for section #1 17028b93c64SAndrii Nakryiko * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h 17128b93c64SAndrii Nakryiko * but may not be identical 17228b93c64SAndrii Nakryiko * struct btf_sec_func_info for section #2 17328b93c64SAndrii Nakryiko * a list of bpf_func_info records for section #2 17428b93c64SAndrii Nakryiko * ...... 17528b93c64SAndrii Nakryiko * 17628b93c64SAndrii Nakryiko * Note that the bpf_func_info record size in .BTF.ext may not 17728b93c64SAndrii Nakryiko * be the same as the one defined in include/uapi/linux/bpf.h. 17828b93c64SAndrii Nakryiko * The loader should ensure that record_size meets minimum 17928b93c64SAndrii Nakryiko * requirement and pass the record as is to the kernel. The 18028b93c64SAndrii Nakryiko * kernel will handle the func_info properly based on its contents. 18128b93c64SAndrii Nakryiko */ 18228b93c64SAndrii Nakryiko struct btf_ext_header { 18328b93c64SAndrii Nakryiko __u16 magic; 18428b93c64SAndrii Nakryiko __u8 version; 18528b93c64SAndrii Nakryiko __u8 flags; 18628b93c64SAndrii Nakryiko __u32 hdr_len; 18728b93c64SAndrii Nakryiko 18828b93c64SAndrii Nakryiko /* All offsets are in bytes relative to the end of this header */ 18928b93c64SAndrii Nakryiko __u32 func_info_off; 19028b93c64SAndrii Nakryiko __u32 func_info_len; 19128b93c64SAndrii Nakryiko __u32 line_info_off; 19228b93c64SAndrii Nakryiko __u32 line_info_len; 19328b93c64SAndrii Nakryiko 19428b93c64SAndrii Nakryiko /* optional part of .BTF.ext header */ 19528b93c64SAndrii Nakryiko __u32 core_relo_off; 19628b93c64SAndrii Nakryiko __u32 core_relo_len; 19728b93c64SAndrii Nakryiko }; 19828b93c64SAndrii Nakryiko 1994cedc0daSAndrii Nakryiko struct btf_ext { 2004cedc0daSAndrii Nakryiko union { 2014cedc0daSAndrii Nakryiko struct btf_ext_header *hdr; 2024cedc0daSAndrii Nakryiko void *data; 2034cedc0daSAndrii Nakryiko }; 2044cedc0daSAndrii Nakryiko struct btf_ext_info func_info; 2054cedc0daSAndrii Nakryiko struct btf_ext_info line_info; 20628b93c64SAndrii Nakryiko struct btf_ext_info core_relo_info; 2074cedc0daSAndrii Nakryiko __u32 data_size; 2084cedc0daSAndrii Nakryiko }; 2094cedc0daSAndrii Nakryiko 2104cedc0daSAndrii Nakryiko struct btf_ext_info_sec { 2114cedc0daSAndrii Nakryiko __u32 sec_name_off; 2124cedc0daSAndrii Nakryiko __u32 num_info; 2134cedc0daSAndrii Nakryiko /* Followed by num_info * record_size number of bytes */ 214385bbf7bSGustavo A. R. Silva __u8 data[]; 2154cedc0daSAndrii Nakryiko }; 2164cedc0daSAndrii Nakryiko 2174cedc0daSAndrii Nakryiko /* The minimum bpf_func_info checked by the loader */ 2184cedc0daSAndrii Nakryiko struct bpf_func_info_min { 2194cedc0daSAndrii Nakryiko __u32 insn_off; 2204cedc0daSAndrii Nakryiko __u32 type_id; 2214cedc0daSAndrii Nakryiko }; 2224cedc0daSAndrii Nakryiko 2234cedc0daSAndrii Nakryiko /* The minimum bpf_line_info checked by the loader */ 2244cedc0daSAndrii Nakryiko struct bpf_line_info_min { 2254cedc0daSAndrii Nakryiko __u32 insn_off; 2264cedc0daSAndrii Nakryiko __u32 file_name_off; 2274cedc0daSAndrii Nakryiko __u32 line_off; 2284cedc0daSAndrii Nakryiko __u32 line_col; 2294cedc0daSAndrii Nakryiko }; 2304cedc0daSAndrii Nakryiko 23128b93c64SAndrii Nakryiko /* bpf_core_relo_kind encodes which aspect of captured field/type/enum value 23228b93c64SAndrii Nakryiko * has to be adjusted by relocations. 233511bb008SAndrii Nakryiko */ 23428b93c64SAndrii Nakryiko enum bpf_core_relo_kind { 235511bb008SAndrii Nakryiko BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ 23628b93c64SAndrii Nakryiko BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */ 237511bb008SAndrii Nakryiko BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ 23828b93c64SAndrii Nakryiko BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */ 23928b93c64SAndrii Nakryiko BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */ 24028b93c64SAndrii Nakryiko BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */ 2413fc32f40SAndrii Nakryiko BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */ 2423fc32f40SAndrii Nakryiko BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */ 2433fc32f40SAndrii Nakryiko BPF_TYPE_EXISTS = 8, /* type existence in target kernel */ 2443fc32f40SAndrii Nakryiko BPF_TYPE_SIZE = 9, /* type size in bytes */ 245511bb008SAndrii Nakryiko }; 246511bb008SAndrii Nakryiko 24728b93c64SAndrii Nakryiko /* The minimum bpf_core_relo checked by the loader 2484cedc0daSAndrii Nakryiko * 24928b93c64SAndrii Nakryiko * CO-RE relocation captures the following data: 2504cedc0daSAndrii Nakryiko * - insn_off - instruction offset (in bytes) within a BPF program that needs 251511bb008SAndrii Nakryiko * its insn->imm field to be relocated with actual field info; 2524cedc0daSAndrii Nakryiko * - type_id - BTF type ID of the "root" (containing) entity of a relocatable 25328b93c64SAndrii Nakryiko * type or field; 2544cedc0daSAndrii Nakryiko * - access_str_off - offset into corresponding .BTF string section. String 25528b93c64SAndrii Nakryiko * interpretation depends on specific relocation kind: 25628b93c64SAndrii Nakryiko * - for field-based relocations, string encodes an accessed field using 25728b93c64SAndrii Nakryiko * a sequence of field and array indices, separated by colon (:). It's 25828b93c64SAndrii Nakryiko * conceptually very close to LLVM's getelementptr ([0]) instruction's 25928b93c64SAndrii Nakryiko * arguments for identifying offset to a field. 26028b93c64SAndrii Nakryiko * - for type-based relocations, strings is expected to be just "0"; 26128b93c64SAndrii Nakryiko * - for enum value-based relocations, string contains an index of enum 26228b93c64SAndrii Nakryiko * value within its enum type; 2634cedc0daSAndrii Nakryiko * 2644cedc0daSAndrii Nakryiko * Example to provide a better feel. 2654cedc0daSAndrii Nakryiko * 2664cedc0daSAndrii Nakryiko * struct sample { 2674cedc0daSAndrii Nakryiko * int a; 2684cedc0daSAndrii Nakryiko * struct { 2694cedc0daSAndrii Nakryiko * int b[10]; 2704cedc0daSAndrii Nakryiko * }; 2714cedc0daSAndrii Nakryiko * }; 2724cedc0daSAndrii Nakryiko * 2734cedc0daSAndrii Nakryiko * struct sample *s = ...; 2744cedc0daSAndrii Nakryiko * int x = &s->a; // encoded as "0:0" (a is field #0) 2754cedc0daSAndrii Nakryiko * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, 2764cedc0daSAndrii Nakryiko * // b is field #0 inside anon struct, accessing elem #5) 2774cedc0daSAndrii Nakryiko * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) 2784cedc0daSAndrii Nakryiko * 2794cedc0daSAndrii Nakryiko * type_id for all relocs in this example will capture BTF type id of 2804cedc0daSAndrii Nakryiko * `struct sample`. 2814cedc0daSAndrii Nakryiko * 2824cedc0daSAndrii Nakryiko * Such relocation is emitted when using __builtin_preserve_access_index() 2834cedc0daSAndrii Nakryiko * Clang built-in, passing expression that captures field address, e.g.: 2844cedc0daSAndrii Nakryiko * 2854cedc0daSAndrii Nakryiko * bpf_probe_read(&dst, sizeof(dst), 2864cedc0daSAndrii Nakryiko * __builtin_preserve_access_index(&src->a.b.c)); 2874cedc0daSAndrii Nakryiko * 288511bb008SAndrii Nakryiko * In this case Clang will emit field relocation recording necessary data to 2894cedc0daSAndrii Nakryiko * be able to find offset of embedded `a.b.c` field within `src` struct. 2904cedc0daSAndrii Nakryiko * 2914cedc0daSAndrii Nakryiko * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction 2924cedc0daSAndrii Nakryiko */ 29328b93c64SAndrii Nakryiko struct bpf_core_relo { 2944cedc0daSAndrii Nakryiko __u32 insn_off; 2954cedc0daSAndrii Nakryiko __u32 type_id; 2964cedc0daSAndrii Nakryiko __u32 access_str_off; 29728b93c64SAndrii Nakryiko enum bpf_core_relo_kind kind; 2984cedc0daSAndrii Nakryiko }; 2994cedc0daSAndrii Nakryiko 300d7c4b398SAndrii Nakryiko #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 301